The Pizza Theory: Anchovy Expansion, consisting of a set of 16 anchovy toppings and a rulebook, is used with the Pizza Theory board game to present players with an additional challenge.

In addition to removing the opponents' toppings, each player must now work to keep the anchovies from taking over the pie, too. If all 16 anchovies end up on the pie before any player places his toppings, then everyone loses and the anchovies reign supreme!